[Smush Pro] CDN appears inactive in Smush Pro

I'm trying to activate the CDN with Smush Pro; however, I am having issues. When I go into the CDN section of Smush Pro it states that "CDN is not yet active. Configure your settings below and click Activate." When I press the "Save and Activate" button, the button changes to "Activating CDN" and just spins. I've left the web browser window open for hours and the button just spins.